September 2013

Out on a limb: Benefit without bare feet

Jordana's TweetsJordana Bieze Foster, Editor

The minimalist shoe trend may be fading, but interest in finding ways to reap the benefits of barefoot running without actually going barefoot remains strong.

There is general agreement in the biomechanics community and the medical literature that habitual barefoot running is associated with changes in mechanics that are likely to reduce injury risk in most runners. But barefoot running also has a number of image problems. In some running environments, bare feet are vulnerable to the dangers of extreme temperatures, debris, and uneven terrain. Transitioning too quickly from shod to barefoot running can lead to stress fractures and other injuries. And some research suggests that doffing the shoes doesn’t necessarily lead to a forefoot strike or reduced loading in all runners.

That left the door open for an alternative that might offer the benefits of barefoot running while maintaining the benefits of wearing shoes. Minimalist shoes, even the funny looking ones, seemed as if they might fit the bill. But it turns out that making the transition from conventional running shoes to minimalist running shoes can be as challenging as transitioning to barefoot running. And some studies suggest that running in minimalist shoes doesn’t actually offer the same mechanical benefits as barefoot running—possibly because some shoes marketed as minimalist are not really all that minimal in terms of cushioning or heel drop.

The latest development in the effort to simulate the effects of barefoot running, however, seems promising. Running biomechanists have noticed that one characteristic of barefoot running is a faster cadence than shod running. At first this was thought to be simply a byproduct of the shorter strides associated with forefoot striking, since the runner is not lengthening his or her stride by reaching out with the heel. Shorter strides typically lead to faster cadence.

But what if the increased cadence itself was responsible for some of the benefits of barefoot running? Cadence manipulation and barefoot running, studied separately, have been associated with similar effects. And now researchers from the Hospital for Special Surgery in New York City have demonstrated those same similarities in a single group of runners (see, “Increased running cadence simulates some advantages of going barefoot,” page 11).

In two studies presented in early September at the annual meeting of the American Society of Biomechanics in Omaha, NE, analysis of five healthy runners demonstrated that running shod at a cadence 10% higher than normal and running barefoot were both associated with significant decreases in vertical loading rate, knee power, and peak knee flexion angle. The increased-cadence condition was also associated with significant decreases in hip adduction angle, which could be an unanticipated advantage over barefoot running.

Yes, the sample size is small, and the reported effects are acute. But the implications could be huge, especially for runners with foot deformities or other issues that preclude going barefoot. Runners may not have to trade in their favorite shoes or endure an uncomfortable transition period to reduce their risk of injury. They might just have to learn to take more steps per minute.

Now that’s a trend I think a lot of runners would embrace.

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